Piston



C. S. CLARK July 6, 1943.

PISTON Filed Jan. 28, 1942 2 Sheets-Sheet l Cornelius S. Clark,

C. S. CLARK July 6, 1943.

PISTON Filed Jan. 28, 1942 2 Sheets-Sheet 2 a current of air past 7 of the core portion of ing cylindrical here shown, three peripheral grooves which re- Patented July 6, 1943.

UNITED STATES PATENT OFFICE Cornelius ST Qia i-Z NorIoIk, Va. 1 Application January'28 1942, Serial No. 428,611

19 Claims.

This invention relates to improvements in pistons for internal combustion engines, including engines of Diesel type. An object of the invenwall is an integral interrupted annular rib come prising segments 2i tion is to provide simple and effective means for air-cooling such pistons. Another object of the invention is to provide means whereby to set up the oil ring groove of a piston in such manner will be withdrawn therefrom and returned to the crank case, the said current also being preferably directed in a manner to cool the head of the piston. in the accomplishment of these objects dangerous overheating of the piston and carthat excess oil in the groove bonization of excess oil in the oil ring groove are avoided.

Practical modes of carrying out the invention are shown in the accompanying drawings by way of example and description of the invention will proceed with reference to these drawings in which:

Figure 1 is an "elevation; partly in axial section, of a two-partpiston in accordance with the invention, the walls of a cooperating cylinder being also shown in axial section. I

Figure 2 is a bottom plan view of the upper or head portion of the piston of Figure 1. 1

Figure 3 is a bottom plan view of the lower or core portion of the piston of Figure 1.

Figure 4 is an elevation, partly in axial. section,

the piston.

Figure 5 is a partial axial section of the piston on a plane at an angle to the sectional plane of F Figure 6 is-an elevation partly in axial section of a modified form of piston in accordance with the invention.

Figure '7 is an axial section of another form of piston in accordance with the invention, a cooperating wall of a cylinder being also shown in axial section.

Figure 8 is a section on line H of Figure '7.

Figure 9 is a section on line 9-9 of Figure '1.

Figure 10 is a section on line il-IO of Figure 7, and

Figure 11 is Figure 1 showing a modification.

Referring to the drawings and first to Figures 1 to 5, reference numeral ii designates generally a piston which comprises an upper or head portion lrand a lower or core portion i1. Portion l0 comprises a circular top wall I8 and a dependskirt il in which are formed, as

ceive compression rings 20; At the juncture of the inner wall of the skirt portion a partial sectional view like that of 4 withthe top through the passages 35 and are tionedbelow the lower edge of skirt of equal length which are equally spaced by recesses 22. As here shown there are six segments 2i and extending radially from the center of each in the same plane as the lower faces of the segments 2!. The lower surfaces of ribs 23 are upwardly and outwardly inclined in a manner to substantially merge wit the top wallat the segments 2|.

' and of the same width as recesses 22. An axially extending opening or bore 32 is formed in flange 28 immediately beneath each groove 3i.

Formed in portion 25 are wrist pin bosses 33 and, these being provided with coaxial bores which extend through the walls of portion 25.

The top wall 26 is provided with six openings or bore 35 wliich, as here shown, are of reduced cross section as compared to the flange openings 32, and below each opening 35 is a funnel. formation constituted by a countersink in wall 26.

In assembly, the cylindricalportion 25 is inserted in the skirt l9 'until the top wall 2 abuts the stop portions constituted by the segments 2i and boss 24, flange 28 being thus properly posii! to provide an oil ring groove 29 which receives an oil ring 20. Grooves 21 are aligned with recesses 22 and this alignment can be insured by properly relating arrows as at a: and a, Figure 1, which may be marked on the head and core portions prior to assembly. The head portion may-be of any suitable material, although I prefer to use copper, while the core portion may desirably be of: cast iron. The head portion may be shrunk onto the core portion and desirably thetwo are additionally spot welded togethe with the parts thus assembled the openings 35 debouch into a head chamber 31 which is.deflned by the top wall I. of the piston, vening portion of skirt l9. Being thus bounded on all sides, chamber SLmay be referred to as a closed chamber although open to the outside oves 3|, which is a rib 23 integral with. the top wall, these ribs merging in a central boss 24 which has a lower face be snugly received in the partition wall 36 and the interlatter are now outwardly closed by the skirt l9 except at the groove 29. The latter is of such depth that when the oil ring is operatively posidownwardly through grooves 3| and openings 32 past the groove 29. The current thus set up acts to carry downwardly into the crank case the oil which would otherwise tend to accumulate in the groove 29 behind ring 20, and in traversing chamber 31 the air has a cooling effect on the upper portion of the piston. Consequently, overheating of the piston as well as carbonization. of excess oil in the groove 29 is effectively avoided The arrangement illustrated in Figure 11 is similar to that shown in Figure 1 except that in Figure 11 the bottom wall 65 of head or cap 66 is flat throughout and the partition wall 61 of the core is provided with a number; here indicated as six, of upwardly projecting equally spaced stop lugs 68 which are arranged in a circle spaced inwardly somewhat from the inner edges of the grooves 69 so that the upper ends of the latter are in free communication with the chamber I0. Lugs 66 are all of equal height and when the core is assembled with the head they abut the bottom wall 65 so that chamber Ill is provided and a predetermined width of the oil groove H is established. The oil escape passages as at 12 lead from the oil'ring groove in alignment with grooves 69. The partition wall 61 is provided with openings like those previously described.

In Figure 6 the piston 38 is essentially the same as that previously described. The head portion 39 is provided with a greater number of compression ring grooves and is internally threaded for engagement with the externally threaded reduced portion of the core 46. The latter terminates at the radial flange 4| which constitutes a part of the skirt as a whole. The circulating provisions are the same as in the first embodiment.

Referring now to Figures 7 to 10, the piston 42 comprises the head portion 43 and the core portion 44. The head portion is provided with compression ring grooves 45 and with an oil ring groove 46. Below the oil ring groove the piston skirt is provided internally with two arcuate recesses 47 and 48 separated by lands 49 and 50 a most clearlyshown in Figure 9. Three longitudinally extending grooves terminate downwardly in the recess 41 and upwardly at the piston top wall and three similar grooves 52 extend between the top wall and recess 48. Radial openings 53 extend from grooves 52 to the bottom of the oil ring groove,

The core 44 has a cylindrical portion 54 adapted to be closely received in the skirt 43 of the head portion and has a bottom flange 55 secured against the lower end 'ofthe skirt 43. The top wall is imperforate. At one side the core is formed with a downwardly flared baflle 56 which, as here shown, is in the form of a partial cone whose longitudinal edges lie closely adjacent the cylinder wall-51 so that in conjunction with the latter a funnel-like formation is provided. At

the upper end ofthe batlle the side wall of the core is provided with a-laterally elongated slot positely disposed slot 59 communicates with recess 48. The core carries the wrist pin '60 which is .engaged by the connecting rod 6| baflle 56 be-' ing disposed at one side of the plane 'of swing of the connecting rod.

On the down-stroke of the piston, air is compressed between the baflle 56 and adjacent piston wall, passes into recess 41 through slot 58, travels upwardly through slots 5|, across the top chamber 62, down slots 52 to recess 48, and back to the crank case through slot 59. In this manner a flow of cooling air is established across chamber 62 at each down-stroke and as the air passes downwardly through grooves 52 pastopenings 53 anyexcess oil in the oil ring groove 46 is withdrawn and returned to the crank case. While this design of piston is suitable for use in any type of internal combustion engine, it is particularly effective in the Diesel type in view of the very.effective cooling current which is set up. The effectiveness of the funnel action is enhanced by the lateral disposition of the outlet opening 59.

The described embodiments are to be considered as only illustrative of the invention and not restrictive thereof since other variations in the form and arrangement of parts are contemplate under the following claims.

I claim 1. A piston having a top wall and a skirt, a transverse partition spaced below said top wall and defining a chamber with said wall and the intervening skirt portion, an outlet opening for the chamber, an inlet opening for the chamber, and a funnel formation communicating with said inlet opening and faced toward the base of the piston, whereby on the down stroke ,of the piston in use a current will opening through the chamber to the outlet openmg.

2. A piston having a top wall and a skirt, a transverse partition spaced'below said top wall and defining a chamber with said wall and the intervening skirt portion, a passage leading from said chamber along the inner side of the skirt to an outlet opening at the base of the piston, an

oil ring groove in the skirt, a passage connecting said groove with the first-named passage, an inlet opening for the chamber, and a funnel formation communicatin with said inlet opening and faced toward the base of the piston, whereby on the downstroke of the piston in use a current will be set up from the inlet opening through the chamber and said first-named passage to the. outlet opening.

3. A piston according to claim 1, wherein the outlet opening is directed inwardly toward the piston axis.

4. A piston having a closed chamber therein adjacent its top, open-ended passages extending from said chamber toward the base of the piston, said piston having an oil ring groove whose inner portion is in communication with said pas- 58 which communicates with recess 41. An opthe chamber on the downstroke of the piston in use.

5. A piston according to claim 4, wherein said passages are arranged in two opposed groups, wherein two separate arcuate recesses are provided and in which the passages of the two groups terminate respectively, and wherein one of said recesses has an inlet which the air is forced andthe other recess has an outlet opening.

-6. A piston having a top wall and a skirt. a

be set up from the inlet" qpening through downwardly from transverse partition spaced below said top wall and defining a chamber with said, wall and the intervening skirt portion,' an outlet opening for the chamber, an inlet opening for the chamber in said partit on, and a funnel formation at the lower end of said inlet opening faced toward the base of the piston, whereby on the downstroke of the piston in use a current will be set up from the inlet opening through the chamber to the outlet opening.

said groove, and means for forcing air into said chamber and out through said passages.

13. A piston having a top wall and a skirt, a transverse partition spaced below said top wall and defining a chamber with the latter and the intervening skirt portion, an oil ring groove in the skirt belowsaid chamber, passages leading downwardly from said chamber to the inner portion of said groove, oil discharge passages leading downwardly from the bottom portion of said groove and terminating inwardly of the outer wall of the piston, and means for forcing air into said chamber and out through said passages;

14. A piston having a closed chamber therein, an oil ring groove in the piston, passage means connecting said chamber and groove, passage means arranged in draining relation to said groove, and means for forcing air into said chamber and out through said passage means.

8. A piston having a top wall and a skirt, a

transverse partition spaced below said top walland defining a chamber with said wall and the intervening.- skirt portion, an oil ring groove in said skirt portion below said chamber, openended passages extending from said chamber toward the base of the piston past said groove and in communication with the latter, an inlet opening in said partition, and a funnel formation at the lower end of said inlet opening faced toward the base of the piston, whereby on the downstroke of the piston in use a current will be set up from the inlet opening through the chamber and said passagespast said groove.

9. A piston having a top wall and a. skirt, a

' transverse partition spaced belowsaid top wall and dfining a chamber with said wall and the intervening skirt portion, an outlet opening for the chamber, an inlet opening for the chamber, and a downwardly flared bame on the piston cooperative with the adjacent wall of a cylinder to provide a funnel formation in communication with the inlet opening, whereby on the downstroke of the piston in use a current will be set up from the inlet opening through the chamber to the outlet opening.

10. A piston having a closed chamber therein, an oil ring groove in the piston, a passage connecting said chamber with the inner portion of said groove, an oil discharge passage leading downwardly from the bottom portion of said groove, and means for forcing air into said chamber and out through said passages.

11. A piston having a closed chamber therein, an oil ring groove in the piston, a passage connecting said chamber with the inner portion of said groove, an oil discharge passage leading the bottom portion of said groove, and termina 'ng inwardly of the outer wan of the piston, and means for forcing air into said chamber and out through said passages. 12. A piston having a top wall and a skirt, a transverse partition spaced below said topwall and defining a chamber-with the latter and the intervening skirt portion, an oil ring groove in the skirt below said chamber, passages leading downwardly from said chamber to the inner portion of said groove, oil discharge passages leading downwardly from the bottom portion of including a cylindrical portion,

' and an external flange spaced from said closure ber, passages leading 15. A' piston having a closed chamber therein, an oil ring groove in said piston, said groove being sufficiently deep so that when an oil ring is operatively positioned therein an enlarged annular space will exist within said ring, passages connecting said chamber andspace, oil discharge passages leading downwardly from said space, and means for forcing air into said chamber and out through said passages.

16. A piston having a top wall and a skirt, a wrist pin carrier engaged in said skirt and having a top wall defining a chamber with the top wall of the piston and adjacent skirt portion, an oil ring groove in the skirt below said chamber, passages leading downwardly from said chamber to the inner portion of said groove, oil discharge passages leading downwardly from the bottom portion of said groove, and means for forcing air into said chamber and out through said passages.

1'7. -A piston having a top wall and a skirt, a wrist pincarrier engaged in said skirt and having a top wall defining a chamber with the top wall of the piston and the intervening skirt portion, an oil ring groove in the skirt below said chamdownwardly from said chamber to the inner portion of said groove, oil discharge passages leading downwardly from the bottom portion of said groove in alignment with the first-named passages, and means for forcing air into said chamber and out through said passages.

18. A piston comprising a head portion including a hollow cylindrical portion and a top wall closing said cylindrical portion, a core portion a top closure wall,

wall, said core portion being snugly inserted and fixed in said head portion so that a chamber is provided between said top walls, and said flange is spaced below the cylindrical portion of said head portion to provide an oil ring groove, lon itudinal passages formed in one of said cylindrical portions and connecting the chamber and groove,

' and passages formed in said flange in communication with the bottom portion of said groove.

19. A piston according to claim 18, wherein fixed stop means between said top walls determine the extent of insertion of the core portion in the head portion.

I commune s-CLARK. 

